In a conventional image forming apparatus and image reader, when an image is read optically and printed on a paper sheet, the printing results vary due to changes over time and mechanical differences of the image forming apparatus and image reader. When these variations occur, it becomes necessary to perform image correction such as color correction and the like.
In the field of image transmission, methods have been proposed for image correction by storing image correction information relating to individual image readers and image forming apparatuses on a client terminal or server, and combining these information to achieve image correction.
Furthermore, in the field of color copiers, methods have been proposed for printing a correction image via the image forming apparatus by placing an image correction print object manually on an image reading table, and reading the correction image via the image reader to automatically change the image correction information.
However, since correction methods used in conventional image transmission devices utilize image information relating to individual image readers or image forming apparatuses, optimum image correction information of combined image readers and image forming apparatuses is not obtained, and accurate image correction is not achieved. A further disadvantage arises in that image quality deteriorates when discrepancies occur in the image correction information due to changes over time and mechanical differences between the image reader and image forming apparatus.
As to color copiers, another disadvantage is image correction is limited to the image reader and image forming apparatus within a particular color copier, and image correction cannot be attained when image information read by the image reader of a particular color copier is transmitted for printing by another image forming apparatus, and conversely, when image information read by another image reader is transmitted for printing by that particular color copier.